Method of making zirconium compounds



Patented Dec. 7', 1926;

UNITED ST TES PATENT OFFICE."

CHARLES I. ,KINZIE, OFATIAGARA FALLS, NEW YORK,-ASSIGNOR TO THE TITANIUM AIQLOYV MAINE.

No Drawing.

7 My-invention relates to the derivation of zirconium compounds from the decomposition of zirconium ores and minerals, the

most important of which are baddeleyite and zircon (zirconium silicate), which com pounds result chiefly in the form of acid zirconium solutions that may be used there after in; preparing various inorganic and organic salts of zirconium.

The objects of my invention are, among other things, the provision of novel and simplified methods. for converting zircon or addeleyite (containin both zirconium oxide and zirconium sificate) into an acid zirconium solution which may thereafter be utilized and employed for manufacturing various zirconium compoundssuch as composite opacifying pigments for vitreous enamels or for-fabric weighting etc., all at much lower costs than heretofore possible by the use of fusion methods with molten alkalis. p b

According to my invention the zirconium mineral or zircon is decomposed by mixing same in a finely milled state with a restricted amount of alkali, sodium carbonate for example, yielding a charge which when heated to about 900 C. forms a mass that does not shrink materially and retains'to a largeextent its dry character, not yielding even a semi-pasty mass. This'decomposition will result in the formation of a zirconium compound'readilydissolving in dilute acids with the silicon carried into the acid solution along with the zirconium. I

con in the ore used wherfgequal weights of;.

zircon and sodium carbonate were used. I have also discovered that practically no improvement in zircon decomposition results when the amount of sodium carbonate was increased in proportion to the zircon.

Among the practical advantages of my improved decomposition methods and the derivation of desired zirconium compounds, I will'mention the following 1. High temperatures are not employed with the charge remaining throughout the period of roasting as a solid mass which may be heated on the flo r Of mufile furmoracronme COMPANY, or-nnwyomnn. Y., A conrormrroiv or amnion or MAKING :ZIRCONIUM comrounnsf Application filed October 27, 1925. Serial No. 65,243.

.nace and may be handledv as in the cussuc alkali is held. The lower temperatures used also prevent corrosion with accompanying contamination of the products since alkalis are usually more'active at the higher temperatures in the fusion decomposition methods.

4. Economy in the relatively small amount of alkalircquired,'the cost of alkali being considerably less than that of the natural zirconium ores and minerals employed.

zirconium ores and minerals.

In practicing my improved methods it is of advantage to have the zirconium mineral as free as possible from undesired substances, such as compounds of iron, titanium and rare earths, so as to leave less of these impurities in the resulting acid solution.

,When baddeleyite is used a pretreatment with hydrochloric or other mineral acid will remove most of the iron. Such pretreat- 7b 5. Adaptability for treating all types of ments are usually desirable but do not comprise the,essential features of my invention.

My invention may be successfully practiced as follows: I'first mill the zirconium ore as fine as 325' mesh usually by the wet process and mixtherewith an equal weightofsodium carbonate (Na CO Other al- "kalis, such as sodium hydrate, sodium peroxide, and sodium sulphide, or mixtures of these sodium compounds may be used and I have successfully carried out my improved methods of forming a mixture of only 0.6

parts by weight of sodium carbonate to one part of zircon. However I usually use equal parts of zircon and sodium carbonate. This mixture is then roasted at a temperature ranging from 850 C. to 950 0., preferably about 900 C. from one to four lioursdepending on the character of the particular zirconium ore used and the amount of the charge. When employing the most desir able temperature of 900 0., the mass does not shrink materially and retains to a large v is completel with sufficient water, and when discharged from the mill either of the following treatments may be' resorted to. v s

a A. In case of zirconium orescontaining impurities such a chromium, manganese, etc,

which dissolve in water (after roasting operation), it is necessary to dilute with water and give the material several washes to remove objectional impurities, I prefer to do this as in most, cases there is found some chromium, manganese, et'c., whichif washed out will give less trouble in later treatments.

It is also usually 'des i'rableto remove the .water soluble silicates and aluminates when alumina is present. 'The residue from this treatment is now treated with a suitable acid depending upon what zirconium .compound is desired. Usually I refer to use sulphuric acid andfthis can be .0 any dilution that will effectively dissolve the. soluble zirconium'and silicon compoundsff For instance, I have used'sulphur'ic acid of 60% H 80, strength (by weight). When. this is added to the resi due after decantation .of the water-soluble fraction residue or slurry containing say 400' parts '(weight solids to liter of slurry), con-.

' fsiderable heat is developed and zirconium and silicon complexes quickly d ssolve. 'Under these conditions the charge Wlll m short timefbecome a. stiff mass due to. ge-

latinizing of silica and possibly of zirconium.

' If desired such a mass can be dried 'at .say about 200 C to render the silicon compounds insoluble and then by extracting with waterabout.i90% of the zirconium is obtained in solution. The fraction of zirconium which is insoluble in the acidwill inthis case remain with the silica and for this reason the fol-' lowing treatment-B. may be referable.

B. The .chargeistreated w1th dilute acid say-containing 10% sulphuric acid by weight or of any suitable strength thatwill dissolve 7 I. the silicon and soluble zirconium fraction,

but which, when the charge is allowed to settle, will not result in the-setting u of. silicon compounds. Using 10% acid'an al--. lowing say one hour for solution of the soluble fraction (the action being. slower with this diluter acid), and after no further solvent action is apparent, the charge is allowed to stand at room temperature; It will be found that'a more or less granular product settles out leaving a supernatant solution containing practically all" the silicon and about 90% of the zirconium in acid solution.

This solution is "decanted off and the residue is diluted'slightly with'water or preferably by weight to 100 of zirconium ore'i-ntro-i duced. .Upono analysis this residue was found to contain only 15% silica and about 85% zirconia being essentially free of fixed sodium or alkali compounds. Thisresidue can be used as such as a zirconiumozgide of fair degree of purity or it may be treated with concentrate H 86 and upon heating will dissolve forming zirconium sulphate which can be leached out leaving the silica or small amount of "zirconium silicate insoluble. V

The dilute acid solution. containina both silica and zirconium in solution may then be evaporated by any suitable. means and finallyheated at suflicient temperature to render the silica insoluble; Evaporation under -reduced pressure andconsequent lower temperature is very' efi'ective in thatthe solution can be boiled at say (1., aiid evaporation can be carried much ,furtlierwithout the silicon separating out. Such point is reached where silicon compounds begin to separate as will be indicated by appearance of jellylike aggregates; The charge can at this stage he transferred to another vesseland evapo ration continued, or it may be continued in same vessel by simp y reducing or entirely cutting out suction an allowing temperature to rise. The heat is referably'applied externally although it can be applied internally by means of-coils; however external heat is better adapted to this operation. The

charge is finally baked to render the silica tial water washing or residue from roasting operationbe'cause'if a chlorides'olution is dev sired,hydrochloric. acid would be used instead of sulphuric acid; or nitric acid-might be used, if a nitrate solution were desired.

Oxalic or tartaric acid are good solvents for both the silicon and zirconium; in the same sense any acid in which the zirconium "is soluble could be used depending upon -re quirements of case. y

. In certain cases the water extraction and washing out of water soluble impurities mightbe' eliminated and the disintegrated mass treated directly; with acid and treated iao as in the A case or the roasted massfrom.

furnace might be dry milled to fine owder and charged directl to acid or wor ed u with water and acid added. The metho best suited toeach particular case should be used.

The following example will illustrate the workings of my improved methods The zirconium ore is wet mllled to about 325 mesh, or otherwise crushed to such fineness. I

To 100 parts zirconium ore about 100 parts sodium carbonate are introduced after mill cooled. Although I do not confine myself to cooling of charge it might be wefted while warm or hot. The cooled charge is placed in any suitable machine, preferably a pebble mill of intermittent type, and to it isadded suitable amount of water. The mill is run until all aggregates have been broken down and a fine product obtained, this requiring only a few hours. This charge is discharged from mill and diluted with water and after stirring is allowed to stand and the solids to settle.

The alkaline solution is then decanted and this operation repeated a's often as necessary, depending upon circumstances.

If desired, the charge can be filtered and washed. The method is optional.

The washed residue from decantation system of washing, or if in-the form of a filter cake, is'worked up with water using about three parts water to one of solids.

Dilute acid is then added in amount'slightly in excess of that required to normally combine with the fixed sodium and'soluble zirconium; for instance, for 100 parts of zirconium ore introduced about 160 parts by weight of actual H 80 may be used, which is diluted to say 10% strength before using.

A The acid is stirred into charge and stirring is continued until solution has run its full course; then the charge is allowed to settle and the acid liquor containing both zirconium and" silicon in solution is decanted. Dilute acid is added to residue and again settled and this decanted liquir can he used in taking up fresh charge.

' The acid solution is then evaporatedin any suitable way, and the silicon rendered insoluble; then the charge upon leaching with water yields the zirconium in solution.

The zirconium sulphate solution obtained in this manner can be used as a starting point for preparation of other zirconium divided form with a com ounds such as various salts or the oxide for use as opaquing agent, etc.

I clalm as my invention: v I t 1. The method ofltreating zlrconlum ores,

which'comprises mixing said ores with an alkali and heating the charge without fusion but with decomposition of said'materlal resulting in a zirconium compound solublein dilute acids.

2. The method of treating zirconium ores, wh ch comprises mixing said ores with a sub stantially equal quantity of an alkali and heating the charge without fusion but With decomposition of said material resulting in a zirconium compound soluble in dilute acids.

3. The method of treating zirconium ores, which comprises mixing said ores with an alkali and heating the charge to between 850 C. and 950 C. without fusing the mass and without material shrinkage thereby resulting in zirconum compound soluble in dilute acids.

4, The method of treating zirconium ores, which comprises mixing said ores with a substantially equal quantity of an alkali and heatin the charge to between 850 C. and

950 wihout fusing the massand without material shrinkage thereby resulting in a zirconium compound soluble in dilute acids.

5. The method of treating zirconium ores,

which comprises mixing said ores in finely divided form with an alkali and heating the charge without fusion but with decomposition of said material resulting in a zirconium compound soluble in dilute acids.

6. The method of treating zirconium ores, which comprises mixing said ores in finelysubstantially equal quantity of an alkali and heating the charge without fusion but with decomposition of said material resulting in a zirconium compound soluble in dilute acids.

7. The method of treating zirconium ores, which comprises mixing said ores in finelydivided form with an alkali and heating the charge to between 850 C. and 950 C. wl hlllt out fusing the mass and without material shrinkage, thereby resulting in a zirconium compound soluble in dilute acids.

, 8. The method of treating zirconium ores, which comprises mixing said ores in finelydivided form with a substantially equal quantity of an alkali and hea ing the charge to between 850 C. and 950 C. without fusing the mass and without ma erial shrinkage thereby resulting in a zirconium compound soluble in dilute acids.

9. The method of converting natural zirconium silicate or z rcon into an acid soluble zirconium compound which comprises heating said zircon with an alkali without fusion but with-decomposition of the z rcon, mixing the roasted product with dilute acid to solution of silicon and soluble zirconium compounds, settling the charge and decanting therefrom the acid li uor containing silicon and zirconium in so ution, and drying the residual'zirconium compound;

.10. The method of converting natural zirconium silicate or zircon into an acid so1u-" ble zirconium compound which comrises heating said zircon between 850 C. an 950 C. with asubstantiallyequal quantity of an alkali without fusion but with decompositionof the'zircon, mixing the roasted product with dilute acidto solution of silicon and soluble zirconium compounds, settling the chargeand decanting therefrom the acid liquor containing silicon and zirconium in solution, and drying the residual zirconium compound.

11. The method of converting natural zirconium silicate or zircon into an acid soluble zirconium compound which comprises heat 7 ingsaid zircon with sodium carbonate without fusion but with decomposition of the zir-- con, mixing the roastedv product with dilute 1 acid to solution of silicon and soluble zirconium compounds, settling the charge and decanting therefrom the acid liquor containing silicon and zirconium in solution, and drying the residual zirconium compound.

9 12.- The method of converting natural zir-' conium silicate or zircon into an acid soluble zirconium compoundlwhich comprises'heating saidzircon between 850 C. and 950 C.

dium carbonatewith said silicatea'nd heat-'- with a substantially equal" quantity of s05 dium carbonate withoutjusion-hut' with decomposition of-the zircon, mixing the roasted product with diluteacidto" Solution of silicon and soluble zirconium compounds,

settling the charge and decanting therefrom .the ac1d liquor containing silicon and zircomum in so1ution, and dryi n'g' the-residual zirconium compound.

a 13. In the derivation 01 i atm soluble zirconium compound from zirconium sili cate, the steps which consist in mixing soing the charge to about 900 C. without fusion but with substantial decomposition of.

' said zircon um silicate.

14. In the derivation of" an acid. soluble zirconium "compound from zirconium silif cate, the steps Wl'llCh consist in mix nga substantially equal quantity'of sodium carbonate 'with said silicate and heating'the charge to about 900 C. without fusion .but. with substantial decompositign of. said airconium silicate. 1 I a 15. In treating a zirconium ore to obtain an acid soluble zirconium compound, the

consists in heating sald ore 1n dered alkali resulting in a'dry unfused mass with substantialv decomposition of said ore without shrinking the mass *and forming a zirconium compound soluble in dilute'acids. .17. in treating a ZlI'COIllllID ore to obtain an acid soluble zirconium compound, the step which consists in heating said ore in finelyequal amount of an alkali to substantial decomposition -of said ore. witliout shrinlrmg the mass.

step which consists in heating said ore in finely-divided .form mixed with a substantially equal amount of an alkali to substan tial decomposition of said ore without shrinking the mass and.- forming a zirconium compound soluble in dilute acids.

-an acid soluble zirconium compound, the

st? jvi ed mixture of said ore and sodium carbonate in substantially equal parts by weight between 850 C. and 950C. without fusion but. with, substantial decompositionfof zirconiumv forming a compound soluble in dilut,eacid.'.

, 20. In treating a zirconium ore to obtain an acid soluble compound, the'steps which consist'iriheatmg said ore mixed. with a sub-4 divided form mixed with a substantially- 18. In treatinga zirconiumore toolitain an acid soluble zirconium compound, the- 19. In treating a zirconiunr-ore to obtain which consists in'nheating a finely-distantially equal quantity of sodium carbonate without fusion but with substantial decomposition of said ore, leaching the resulting product,andmixing the residue with dilute acid.

. 21. In treating a'z'rconium ore to obtain .,an acid soluble compound, the steps which substantially equa quantity of sodium car bonate without fusion but with substantial Q- decomposit on' of said'ore, leaching the .re-'

consist in .heatin said; ore mixed with a 7 suiting product, and mixing the residue with dilutesulphuric acid.

CHARLES J. KINZIE. 

